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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/105769] [11/12/13 Regression] program
 segmentation fault with -ftree-vectorize and nested lambdas
Date: Thu, 02 Jun 2022 08:10:46 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105769

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.4
      Known to work|                            |10.3.0
      Known to fail|                            |11.3.0, 12.1.0
            Summary|program segmentation fault  |[11/12/13 Regression]
                   |with -ftree-vectorize and   |program segmentation fault
                   |nested lambdas              |with -ftree-vectorize and
                   |                            |nested lambdas

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
It segfaults doing an indirect call

#0  0x0000000000000001 in ?? ()
#1  0x0000000000400c9d in std::_Function_base::~_Function_base (
    this=3D<optimized out>, this=3D<optimized out>)
    at
/home/space/rguenther/install/gcc-11.3/include/c++/11.3.0/bits/std_function=
.h:244
#2  0x00000000004011f1 in std::function<unsigned long (unsigned
long)>::~function() (this=3D<optimized out>, this=3D<optimized out>)
    at
/home/space/rguenther/install/gcc-11.3/include/c++/11.3.0/bits/std_function=
.h:334
#3  print_cov_ratio<ab> () at /tmp/t.C:86
#4  main () at /tmp/t.C:122

with -fno-lifetime-dse it works fine.  I suspect that either GCC or the
source gets things wrong WRT object lifetime in the maze of lambdas.

It's interesting that with -fsanitize=3Dundefined added we still vectorize
but exactly a single load/store:

t.C:65:3: optimized: basic block part vectorized using 16 byte vectors

and then it still crashes.

   0x0000000000401027 <+97>:    mov    %rbx,%rdi
   0x000000000040102a <+100>:   call   *%rbp
=3D> 0x000000000040102c <+102>:   add    $0x8,%rsp
(gdb) p $rbp
$1 =3D (void *) 0x1

More investigation is needed.=